Sensitivity to the CP-violation parameter φ2 at a B factory

We report on a detailed simulation study on how well we can measure the CP-violation parameter φ2 (or α), an angle of the unitarity triangle at a B factory, and how it depends on the calorimeter resolution. An accuracy of δ sin 2φ2 = 0.092 can be achieved through the B0(B0) → ϱ±π∓ decay mode, when we assume that each branching ratio is 3 × 10−5 and the integrated luminosity is 1041 cm−2. The dependence of the accuracy on the calorimeter resolution is found not to be too critical.